text: Middens are excellent traps for pollen derived from the local and regional surroundings either via the alimentary channel of the animals (excreted in pellets) or via deposition on the middens. The airborne pollen rain is incorporated by (1) collecting on the surface of the midden, (2) being brought in on the fur of the hyraxes, or (3) being ingested as dust on dietary items such as plant leaves or drinking water. The dietary component may also represent the ingestion of flowers, which may result in the occasional over-representation of pollen of certain plant species in the pellet fraction of certain middens. A clear benefit of midden pollen spectra over wetland pollen spectra is that they may more clearly reflect terrestrial vegetation, without the high proportions of hydrophilic elements found in wetland sequences, which is particularly problematic in some dryland pollen records. Furthermore, as the pollen found in hyraceum is not exclusively wind-transported, usually under-represented entomophilous plants are more clearly represented.
  Preservation of pollen sealed in hyraceum is usually very good, but the degradation of pollen grains has been occasionally observed in loose pellets or middens semi-exposed to the elements, such as in dolerite shelters in the central grassland region of South Africa, where some Asteraceae pollen have apparently lost their ektexine (L. Scott, unpublished observation). Compared to other available palaeoarchives in the region, such as fluvial sediments or paleosols, and to more widely used pollen records from peat bog and lakes, middens contain high fossil pollen concentrations; usually between 1 and 2 x 10 pollen grains per gram of sample. Pollen concentrations are high even in poorly productive ecosystems such as the Namib Desert margins. Concentrations increase markedly when analysing pollen contents from pellets, reaching 5-30 x 10 pollen grains/gram of sample.